title: Comparison of 3D TOF-MRA and 3D CE-MRA at 3T for imaging of intracranial aneurysms.
abstract: OBJECTIVE
  To compare 3T elliptical-centric CE MRA with 3T TOF MRA for the detection and characterization of unruptured intracranial aneurysms (UIAs), by using digital subtracted angiography (DSA) as reference.
  
  
  METHODS
  Twenty-nine patients (12 male, 17 female; mean age: 62 years) with 41 aneurysms (34 saccular, 7 fusiform; mean diameter: 8.85 mm [range 2.0-26.4mm]) were evaluated with MRA at 3T each underwent 3D TOF-MRA examination without contrast and then a 3D contrast-enhanced (CE-MRA) examination with 0.1mmol/kg bodyweight gadobenate dimeglumine and k-space elliptic mapping (Contrast ENhanced Timing Robust Angiography [CENTRA]). Both TOF and CE-MRA images were used to evaluate morphologic features that impact the risk of rupture and the selection of a treatment. Almost half (20/41) of UIAs were located in the internal carotid artery, 7 in the anterior communicating artery, 9 in the middle cerebral artery and 4 in the vertebro-basilar arterial system. All patients also underwent DSA before or after the MR examination.
  
  
  RESULTS
  The CE-MRA results were in all cases consistent with the DSA dataset. No differences were noted between 3D TOF-MRA and CE-MRA concerning the detection and location of the 41 aneurysms or visualization of the parental artery. Differences were apparent concerning the visualization of morphologic features, especially for large aneurysms (>13 mm). An irregular sac shape was demonstrated for 21 aneurysms on CE-MRA but only 13/21 aneurysms on 3D TOF-MRA. Likewise, CE-MRA permitted visualization of an aneurismal neck and calculation of the sac/neck ratio for all 34 aneurysms with a neck demonstrated at DSA. Conversely, a neck was visible for only 24/34 aneurysms at 3D TOF-MRA. 3D CE-MRA detected 15 aneurysms with branches originating from the sac and/or neck, whereas branches were recognized in only 12/15 aneurysms at 3D TOF-MRA.
  
  
  CONCLUSIONS
  For evaluation of intracranial aneurysms at 3T, 3D CE-MRA is superior to 3D TOF-MRA for assessment of sac shape, detection of aneurysmal neck, and visualization of branches originating from the sac or neck itself, if the size of the aneurysm is greater than 13 mm. 3T 3D CE-MRA is as accurate and effective as DSA for the evaluation of UIAs.
authors.affiliation: Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences - 2nd University of Naples, Italy. Electronic address: mario.cirillo@unina2.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Cirillo
authors.forename: Francesco
authors.initials: F
authors.lastname: Scomazzoni
authors.forename: Luigi
authors.initials: L
authors.lastname: Cirillo
authors.forename: Marcello
authors.initials: M
authors.lastname: Cadioli
authors.forename: Franco
authors.initials: F
authors.lastname: Simionato
authors.forename: Antonella
authors.initials: A
authors.lastname: Iadanza
authors.forename: Miles
authors.initials: M
authors.lastname: Kirchin
authors.forename: Claudio
authors.initials: C
authors.lastname: Righi
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Anzalone
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002532:Intracranial Aneurysm / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 3D contrast enhanced MRA; 3D time of flight MRA; 3T; Digital subtraction angiography; Intracranial aneurysm; Magnetic resonance angiography